Answer
$C = 8.0~\mu F$
Work Step by Step
We can see that resonance occurs when $\omega_d = 25,000~rad/s$
At resonance, $X_L = X_C$
We can find $C$:
$X_L = X_C$
$\omega_d~L = \frac{1}{\omega_d~C}$
$C = \frac{1}{\omega_d^2~L}$
$C = \frac{1}{(25,000~rad/s)^2~(200\times 10^{-6}~H)}$
$C = 8.0~\mu F$
